Water is able to be distilled by a process of boiling the water to produce a water vapour. The vapour is substantially free of salt and other contaminants, thus allowing for the subsequent condensation of the vapour to produce a substantially salt-free potable or un-contaminated purified water, leaving a concentrated waste solution (a brine) of salt or other contaminants to be dealt with and removed in an appropriate manner.
The efficiency of such a process can be improved by reducing the pressure above the water to less than its vapour pressure (less than atmospheric pressure), in order to lower the boiling point of the water and thus lower the energy requirements. However, there is of course a balance between the added cost and complexity of operating a system under a vacuum, and the efficiency and cost improvements available through operating at lower temperatures.
Another benefit of such a system is that it permits the introduction of a compressor in the vapour line to increase the pressure of the vapour and thereby increase its temperature, allowing the heat then stored in the vapour to be used as a heat source for the boiling of the water. Indeed, as the heat is extracted from the vapour to boil the water, the vapour can be condensed to release its heat, providing a reasonably energy efficient process for the production and further processing of the purified, decontaminated, reclaimed or potable water.
It is an aim of the present invention to provide an improved vacuum distillation apparatus.